My interest is in linking all video games information together. So a link from Redump.org would take you to Wikidata, from Wikidata you could visit Metacritic, MobyGames, or Giant Bomb. Or somebody could write a script to pull those links from Wikidata. Theoretically, it could auto-generate missing entries, but the community would need to drop their "biographies-only" focus and start working on other topics.

There also issues of "re-use" I'd like to address, like the XML .dat dumps have no IDs to get back to the site.

Well, keep in mind one thing… The Redump ID is merely a database convenience. The XML files you are looking at (The DAT files) are NOT complete data dumps. most of the data is in fact contained on the site's DB, whereas the .dat file is a special-purpose format for file management software. To have a complete picture of the data, you need at least both sets.

moreover, keep in mind Redump is a media preservation project. Each single ID refers to a single piece of physical media the group has documented (i.e. dumped, verified, and collected metadata for). This means that an ID won't be uniquely associated to a video game, but to a specific disc of a specific edition of said game.

It would be great to meet in chat over on discord as creating a broader KG of videogames is something I think is very intersting, but perhaps needs a little more pre-work than simply starting from the Redump IDs.

While Wikidata claims to be a knowledge graph, it isn't a priority. Those are 1) centralize the language list for each article (instead of having bots copy them around) and 2) provide data for the corresponding Wikipedia articles. This is how they can have a notability policy.